Files
openlayers/lib/OpenLayers/Handler/MouseWheel.js
ahocevar 8701a54603 Cloning event for use in delayed function
In IE, where window.event is used, the event can change during the delay.
To avoid this, we store the event properties in a new object.
2012-12-07 21:09:09 +01:00

258 lines
8.7 KiB
JavaScript

/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the 2-clause BSD license.
* See license.txt in the OpenLayers distribution or repository for the
* full text of the license. */
/**
* @requires OpenLayers/Handler.js
*/
/**
* Class: OpenLayers.Handler.MouseWheel
* Handler for wheel up/down events.
*
* Inherits from:
* - <OpenLayers.Handler>
*/
OpenLayers.Handler.MouseWheel = OpenLayers.Class(OpenLayers.Handler, {
/**
* Property: wheelListener
* {function}
*/
wheelListener: null,
/**
* Property: interval
* {Integer} In order to increase server performance, an interval (in
* milliseconds) can be set to reduce the number of up/down events
* called. If set, a new up/down event will not be set until the
* interval has passed.
* Defaults to 0, meaning no interval.
*/
interval: 0,
/**
* Property: delta
* {Integer} When interval is set, delta collects the mousewheel z-deltas
* of the events that occur within the interval.
* See also the cumulative option
*/
delta: 0,
/**
* Property: cumulative
* {Boolean} When interval is set: true to collect all the mousewheel
* z-deltas, false to only record the delta direction (positive or
* negative)
*/
cumulative: true,
/**
* Constructor: OpenLayers.Handler.MouseWheel
*
* Parameters:
* control - {<OpenLayers.Control>}
* callbacks - {Object} An object containing a single function to be
* called when the drag operation is finished.
* The callback should expect to recieve a single
* argument, the point geometry.
* options - {Object}
*/
initialize: function(control, callbacks, options) {
OpenLayers.Handler.prototype.initialize.apply(this, arguments);
this.wheelListener = OpenLayers.Function.bindAsEventListener(
this.onWheelEvent, this
);
},
/**
* Method: destroy
*/
destroy: function() {
OpenLayers.Handler.prototype.destroy.apply(this, arguments);
this.wheelListener = null;
},
/**
* Mouse ScrollWheel code thanks to http://adomas.org/javascript-mouse-wheel/
*/
/**
* Method: onWheelEvent
* Catch the wheel event and handle it xbrowserly
*
* Parameters:
* e - {Event}
*/
onWheelEvent: function(e){
// make sure we have a map and check keyboard modifiers
if (!this.map || !this.checkModifiers(e)) {
return;
}
// Ride up the element's DOM hierarchy to determine if it or any of
// its ancestors was:
// * specifically marked as scrollable (CSS overflow property)
// * one of our layer divs or a div marked as scrollable
// ('olScrollable' CSS class)
// * the map div
//
var overScrollableDiv = false;
var allowScroll = false;
var overMapDiv = false;
var elem = OpenLayers.Event.element(e);
while((elem != null) && !overMapDiv && !overScrollableDiv) {
if (!overScrollableDiv) {
try {
var overflow;
if (elem.currentStyle) {
overflow = elem.currentStyle["overflow"];
} else {
var style =
document.defaultView.getComputedStyle(elem, null);
overflow = style.getPropertyValue("overflow");
}
overScrollableDiv = ( overflow &&
(overflow == "auto") || (overflow == "scroll") );
} catch(err) {
//sometimes when scrolling in a popup, this causes
// obscure browser error
}
}
if (!allowScroll) {
allowScroll = OpenLayers.Element.hasClass(elem, 'olScrollable');
if (!allowScroll) {
for (var i = 0, len = this.map.layers.length; i < len; i++) {
// Are we in the layer div? Note that we have two cases
// here: one is to catch EventPane layers, which have a
// pane above the layer (layer.pane)
var layer = this.map.layers[i];
if (elem == layer.div || elem == layer.pane) {
allowScroll = true;
break;
}
}
}
}
overMapDiv = (elem == this.map.div);
elem = elem.parentNode;
}
// Logic below is the following:
//
// If we are over a scrollable div or not over the map div:
// * do nothing (let the browser handle scrolling)
//
// otherwise
//
// If we are over the layer div or a 'olScrollable' div:
// * zoom/in out
// then
// * kill event (so as not to also scroll the page after zooming)
//
// otherwise
//
// Kill the event (dont scroll the page if we wheel over the
// layerswitcher or the pan/zoom control)
//
if (!overScrollableDiv && overMapDiv) {
if (allowScroll) {
var delta = 0;
if (!e) {
e = window.event;
}
if (e.wheelDelta) {
delta = e.wheelDelta;
if (delta % 160 === 0) {
// opera have steps of 160 instead of 120
delta = delta * 0.75;
}
delta = delta / 120;
} else if (e.detail) {
// detail in Firefox on OS X is 1/3 of Windows
// so force delta 1 / -1
delta = - (e.detail / Math.abs(e.detail));
}
this.delta = this.delta + delta;
if(this.interval) {
window.clearTimeout(this._timeoutId);
// store e because window.event might change during delay
var evt = OpenLayers.Util.extend({}, e);
this._timeoutId = window.setTimeout(
OpenLayers.Function.bind(function(){
this.wheelZoom(evt);
}, this),
this.interval
);
} else {
this.wheelZoom(e);
}
}
OpenLayers.Event.stop(e);
}
},
/**
* Method: wheelZoom
* Given the wheel event, we carry out the appropriate zooming in or out,
* based on the 'wheelDelta' or 'detail' property of the event.
*
* Parameters:
* e - {Event}
*/
wheelZoom: function(e) {
var delta = this.delta;
this.delta = 0;
if (delta) {
e.xy = this.map.events.getMousePosition(e);
if (delta < 0) {
this.callback("down", [e, this.cumulative ? delta : -1]);
} else {
this.callback("up", [e, this.cumulative ? delta : 1]);
}
}
},
/**
* Method: activate
*/
activate: function (evt) {
if (OpenLayers.Handler.prototype.activate.apply(this, arguments)) {
//register mousewheel events specifically on the window and document
var wheelListener = this.wheelListener;
OpenLayers.Event.observe(window, "DOMMouseScroll", wheelListener);
OpenLayers.Event.observe(window, "mousewheel", wheelListener);
OpenLayers.Event.observe(document, "mousewheel", wheelListener);
return true;
} else {
return false;
}
},
/**
* Method: deactivate
*/
deactivate: function (evt) {
if (OpenLayers.Handler.prototype.deactivate.apply(this, arguments)) {
// unregister mousewheel events specifically on the window and document
var wheelListener = this.wheelListener;
OpenLayers.Event.stopObserving(window, "DOMMouseScroll", wheelListener);
OpenLayers.Event.stopObserving(window, "mousewheel", wheelListener);
OpenLayers.Event.stopObserving(document, "mousewheel", wheelListener);
return true;
} else {
return false;
}
},
CLASS_NAME: "OpenLayers.Handler.MouseWheel"
});